Propulsion means for projectiles



July 17, 1962 c w. MUSSER 3,044,363

PROPULSION MEANS FOR PROJECTILES Filed April 28, 1960 2 Sheets-Sheet N W WWW INVENTOR. G WALTON MUSSER y" a-J. wdvw ATTORNEYS July 17, 1962 c W.YMUSSER 3,044,363

PROPULSION MEANS FOR PROJECTILES Filed April 28, 1960 v 2 Sheets-Sheet 2 ML L T N q a J, g N

4 8 IO N N' INVENTOR. O WALTON MUSSER ATTORNEYS United States Patent Ofifice 3,044,353 Pate'nted July 17, 1962 3,044,363 1 PROPULSION MEANS FOR PROJECTILES C Walton Musser, Beverly, Mass., assignor to the United States of America as represented by the Secretary of the Army Filed Apr. 28, 1960, Ser. No. 25,491

2 Claims. (Cl. '898) (Granted under Title 35, US. Code (1952), sec. 266) An important advantage of this method is that the force applied to the projectile is readily adjustable and may be increased to a point where the trajectory of the projectile is more nearly fiat than heretofore realized. An additional advantage is that a relatively small cartridge may be utilized to initiate the movement of the projectile. This materially increases the number of rounds that can be fired in a given time, especially in the case of an automatic rifle where the bolt shuttles back and forth.* A further advantage is a reduction in the weight of the cartridge which simplifies the loading operation.

Heretofore, one of the greatest drawbacks to the use of liquid propellants has been the problem of igniting a mass of such propellant uniformly. For example, to introduce a chamber flow of liquid propellant behind the projectile and then ignite this mass of liquid propellant under controlled conditions has proven to be a very difiicult problem. At the present time, it has only been accomplished with a fair degree of success by very care- .fully controlling the ignition and the amount of ullage in the chamber.

There is no difiiculty, however, in igniting small lots of liquid propellant uniformly. The present invention achieves this result by providing the gun barrel with a plurality of annular slots spaced longitudinally along the barrel and having a plurality of ports opening into the barrel. Means, such as an explosive cartridge, are provided to initiate movement of the projectile and to generate a gas which functions to fire the liquid propellant of the different slots as they are successively exposed by the movement of the projectile. Under these conditions, only small amounts of liquid propellant are ignited at a time and the ignition is more uniform.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims.

Referring to the drawings:

FIG. 1 is a view, partly in section, illustrating one form of the invention,

FIG. 2 is a section taken on the line 2-2 of FIG. 1, and

FIG. 3 is a top view of the gun.

These figures show a barrel which comprises a forward part 10 and a rear part 11. It will be noted that the rear end of the part 10 is reduced in diameter and has a plurality of slots 12 each of which communicates with the bore of the barrel through a plurality of ports 13. The

reduced part of the part 10 is preferably slightly tapered so that there is no leakage between the slots 12 when the part 11 is screwed onto the part 10.

The barrel 10-11 is shown as containing a cartridge which includes a projectile 1'4 and a case 15 which may enclose a relatively light charge and be relatively short in length. To the rear of the case 15 are a breech 16 and an electric primer 17.

Means shown as a plurality of inlets 18 with screw top covers 19 are provided for making the liquid propellant available for injection into the slots 12 through passageways 31. Obviously, other means may be provided for this purpose.

'For injecting the liquid propellant into these various slots, there are provided a plurality of cylinders 20 each having a piston 21 fixed at its rear end to a bar 22 which is held in its illustrated position by a trigger 23.

Between the bar 22 and a support 24 is a strong spring 25 which surrounds a pair of telescoped tubes one of which is fixed to the bar 22 and the other of which is fixed to the support 24.

A pin 26, spring biased to its illustrated position, is arranged to be engaged by the bar 22 and to release a locking pin 27. This pin has an arm 28 which functions to close a switch 29.

In the operation of the gun, the pistons 21 are locked in their rearward position as illustrated and an appropriate amount of liquid propellant is put into each of the cylinders 20. The cartridge 1'4-15 is then inserted and locked in the barrel. Under these conditions, pulling the trigger 23 releases the bar 22 which moves the pistons 21 to injectthe liquid propellant through passageways 3 1 into the slots 12 and, at the end of its travel moves the pin 26 so'that the locking rod 27 drops, or is forced downwardly by a spring, locking the bar 22 in place and closing the switch 29 which fires the cartridge 1415. The fact that the liquid propellant is injected into the grooves tangentially, as indicated by FIG. 2, insures that no undesired amount of the propellant gets into the barrel prior to its ignition.

Ignition under these conditions is markedly helped by the configuration of, the ignition path since a sharp shock tends to ignite most of the liquid propellants and the entrance of the burning powder gas into the annular cavities as the projectile uncorks their ports produces a severe shock. For example, probo-nitrate and ethyl-nitrate are sensitive to sharp shocks, particularly adiabatic compression shocks.

I claim:

1. In a gun, the combination of an explosive cartridge, a projectile, a barrel having a breech,

means forming a plurality of annular cavities of rectangular cross section forwardly of said breech and spaced apart along said barrel, each of said cavities opening into the bore of said barrel thru a plurality of ports,

a plurality of cylinders each containing a liquid propellant,

a plurality of substantially cylindrical passageways in said bore connecting each of said cylinders with a different one of said cavities, said passageways being transverse to the bore and generally tangentially oriented with respect to said cavities,

a plurality of pistons each movable in a difierent one of said cylinders,

a bar adjacent said pistons,

means for imparting to said bar a thrust urging said pistons into said cylinder whereby said propellant is simultaneously propelled into each of said cavities and caused to circulate therearound at a velocity which maintains said propellant therein until passed by said projectile,

a pin movable by the action of said bar at the completion of said thrust,

and actuating means including a locking rod and-a switch for firing said explosive cartridge actuated by movement of said pin.

2. In a gun, the combination of an explosive cartridge, a projectile, a barrel having a breech,

piston into said cylinder causing said propellant to be propelled into said cavity at a velocity which maintains said propellant circulating in said cavity around said bore until passed by said projectile,

a pin movable by the action of said bar at the completion of said thrust,

and actuating means including a locking rod and a switch for firing said explosive cartridge actuated by movement of said pin.

References Cited in the file of this patent UNITED STATES PATENTS Haskell Oct. 11, 1892 Iamerson Oct. 28, 1919 Francis Oct. 10, '1944 Treat Jan. 26, 1960 

